4,289 research outputs found
Vigorous star formation hidden by dust in a galaxy at
Near-infrared surveys have revealed a substantial population of enigmatic
faint galaxies with extremely red optical-to-near-infrared colours and with a
sky surface density comparable to that of faint quasars. There are two
scenarios for these extreme colours: (i) these distant galaxies have formed
virtually all their stars at very high redshifts and, due to the absence of
recently formed stars, the colours are extremely red and (ii) these distant
galaxies contain large amounts of dust, severely reddening the rest-frame
UV--optical spectrum. HR10 () is considered the archetype of the
extremely red galaxies. Here we report the detection of the continuum emission
from HR10 at 850m and at 1250m, demonstrating that HR10 is a very
dusty galaxy undergoing a major episode of star formation. Our result provides
a clear example of a high-redshift galaxy where the star formation rate
inferred from the ultraviolet luminosity would be underestimated by a factor up
to 1000, and shows that great caution should be used to infer the global star
formation history of the Universe from optical observations only.Comment: 12 pages, 1 figure, Nature, in press (30 April 1998
The Spanish conquest and the Maya collapse: how ‘religious’ is change?
The phenomenon of the Spanish Conquest of the Maya region suggests strongly that, in the process of socio-cultural transformation, ‘religion’ has no meaning as a concept with its own particular dynamic. There is no such thing as ‘religious’ change that is not also tied to other sorts of changes and indeed to continuity. One dramatic change was the adoption by whole communities, or large segments of communities, of Christian burial practice in which the body was placed in the supine position, head to the west, facing east. Christian burial is seen to represent ‘religious conversion’ but it was one of a broad sweep of changes in how power was gained and wealth appropriated, and the way in which killing was socially sanctioned through warfare. Evidence is accumulating from sites in Belize that a significant change in burial practice also took place at time of the Maya collapse in the ninth and tenth centuries. The question that remains to be answered is whether or not the new interment practices were part of a pattern which, like the burials of the Conquest period, reflected broader socio-cultural transformations
Duration of shedding of respiratory syncytial virus in a community study of Kenyan children
Background: Our understanding of the transmission dynamics of respiratory syncytial virus (RSV) infection will be better informed with improved data on the patterns of shedding in cases not limited only to hospital admissions.
Methods: In a household study, children testing RSV positive by direct immunofluorescent antibody test (DFA) were enrolled. Nasal washings were scheduled right away, then every three days until day 14, every 7 days until day 28 and every 2 weeks until a maximum of 16 weeks, or until the first DFA negative RSV specimen. The relationship between host factors, illness severity and viral shedding was investigated using Cox regression methods.
Results: From 151 families a total of 193 children were enrolled with a median age of 21 months (range 1-164 months), 10% infants and 46% male. The rate of recovery from infection was 0.22/person/day (95% CI 0.19-0.25) equivalent to a mean duration of shedding of 4.5 days (95%CI 4.0-5.3), with a median duration of shedding of 4 days (IQR 2-6, range 1-14). Children with a history of RSV infection had a 40% increased rate of recovery i.e. shorter duration of viral shedding (hazard ratio 1.4, 95% CI 1.01-1.86). The rate of cessation of shedding did not differ significantly between males and females, by severity of infection or by age.
Conclusion: We provide evidence of a relationship between the duration of shedding and history of infection, which may have a bearing on the relative role of primary versus re-infections in RSV transmission in the community
Single-atom imaging of fermions in a quantum-gas microscope
Single-atom-resolved detection in optical lattices using quantum-gas
microscopes has enabled a new generation of experiments in the field of quantum
simulation. Fluorescence imaging of individual atoms has so far been achieved
for bosonic species with optical molasses cooling, whereas detection of
fermionic alkaline atoms in optical lattices by this method has proven more
challenging. Here we demonstrate single-site- and single-atom-resolved
fluorescence imaging of fermionic potassium-40 atoms in a quantum-gas
microscope setup using electromagnetically-induced-transparency cooling. We
detected on average 1000 fluorescence photons from a single atom within 1.5s,
while keeping it close to the vibrational ground state of the optical lattice.
Our results will enable the study of strongly correlated fermionic quantum
systems in optical lattices with resolution at the single-atom level, and give
access to observables such as the local entropy distribution and individual
defects in fermionic Mott insulators or anti-ferromagnetically ordered phases.Comment: 7 pages, 5 figures; Nature Physics, published online 13 July 201
Cell migration leads to spatially distinct but clonally related airway cancer precursors
Background Squamous cell carcinoma of the lung is a common cancer with 95% mortality at 5 years. These cancers arise from preinvasive lesions, which have a natural history of development progressing through increasing severity of dysplasia to carcinoma in situ (CIS), and in some cases, ending in transformation to invasive carcinoma. Synchronous preinvasive lesions identified at autopsy have been previously shown to be clonally related. Methods Using autofluorescence bronchoscopy that allows visual observation of preinvasive lesions within the upper airways, together with molecular profiling of biopsies using gene sequencing and loss-of-heterozygosity analysis from both preinvasive lesions and from intervening normal tissue, we have monitored individual lesions longitudinally and documented their visual, histological and molecular relationship. Results We demonstrate that rather than forming a contiguous field of abnormal tissue, clonal CIS lesions can develop at multiple anatomically discrete sites over time. Further, we demonstrate that patients with CIS in the trachea have invariably had previous lesions that have migrated proximally, and in one case, into the other lung over a period of 12 years. Conclusions Molecular information from these unique biopsies provides for the first time evidence that field cancerisation of the upper airways can occur through cell migration rather than via local contiguous cellular expansion as previously thought. Our findings urge a clinical strategy of ablating high-grade premalignant airway lesions with subsequent attentive surveillance for recurrence in the bronchial tree
Better together?: a naturalistic qualitative study of inter-professional working in collaborative care for co-morbid depression and physical health problems
Background
Mental-physical multi-morbidities pose challenges for primary care services that traditionally focus on single diseases. Collaborative care models encourage inter-professional working to deliver better care for patients with multiple chronic conditions, such as depression and long-term physical health problems. Successive trials from the United States have shown that collaborative care effectively improves depression outcomes, even in people with long-term conditions (LTCs), but little is known about how to implement collaborative care in the United Kingdom. The aim of the study was to explore the extent to which collaborative care was implemented in a naturalistic National Health Service setting.
Methods
A naturalistic pilot study of collaborative care was undertaken in North West England. Primary care mental health professionals from IAPT (Increasing Access to Psychological Therapies) services and general practice nurses were trained to collaboratively identify and manage patients with co-morbid depression and long-term conditions. Qualitative interviews were performed with health professionals at the beginning and end of the pilot phase. Normalization Process Theory guided analysis.
Results
Health professionals adopted limited elements of the collaborative care model in practice. Although benefits of co-location in primary care practices were reported, including reduced stigma of accessing mental health treatment and greater ease of disposal for identified patients, existing norms around the division of mental and physical health work in primary care were maintained, limiting integration of the mental health practitioners into the practice setting. Neither the mental health practitioners nor the practice nurses perceived benefits to joint management of patients.
Conclusions
Established divisions between mental and physical health may pose particular challenges for multi-morbidity service delivery models such as collaborative care. Future work should explore patient perspectives about whether greater inter-professional working enhances experiences of care. The study demonstrates that research into implementation of novel treatments must consider how the introduction of innovation can be balanced with the need for integration into existing practice
Lactate signalling regulates fungal β-glucan masking and immune evasion
AJPB: This work was supported by the European Research Council (STRIFE, ERC- 2009-AdG-249793), The UK Medical Research Council (MR/M026663/1), the UK Biotechnology and Biological Research Council (BB/K017365/1), the Wellcome Trust (080088; 097377). ERB: This work was supported by the UK Biotechnology and Biological Research Council (BB/M014525/1). GMA: Supported by the CNPq-Brazil (Science without Borders fellowship 202976/2014-9). GDB: Wellcome Trust (102705). CAM: This work was supported by the UK Medical Research Council (G0400284). DMM: This work was supported by UK National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC/K000306/1). NARG/JW: Wellcome Trust (086827, 075470,101873) and Wellcome Trust Strategic Award in Medical Mycology and Fungal Immunology (097377). ALL: This work was supported by the MRC Centre for Medical Mycology and the University of Aberdeen (MR/N006364/1).Peer reviewedPostprin
Apraxia and motor dysfunction in corticobasal syndrome
Background: Corticobasal syndrome (CBS) is characterized by multifaceted motor system dysfunction and cognitive disturbance; distinctive clinical features include limb apraxia and visuospatial dysfunction. Transcranial magnetic stimulation (TMS) has been used to study motor system dysfunction in CBS, but the relationship of TMS parameters to clinical features has not been studied. The present study explored several hypotheses; firstly, that limb apraxia may be partly due to visuospatial impairment in CBS. Secondly, that motor system dysfunction can be demonstrated in CBS, using threshold-tracking TMS, and is linked to limb apraxia. Finally, that atrophy of the primary motor cortex, studied using voxel-based morphometry analysis (VBM), is associated with motor system dysfunction and limb apraxia in CBS. Methods: Imitation of meaningful and meaningless hand gestures was graded to assess limb apraxia, while cognitive performance was assessed using the Addenbrooke's Cognitive Examination - Revised (ACE-R), with particular emphasis placed on the visuospatial subtask. Patients underwent TMS, to assess cortical function, and VBM. Results: In total, 17 patients with CBS (7 male, 10 female; mean age 64.4+/2 6.6 years) were studied and compared to 17 matched control subjects. Of the CBS patients, 23.5% had a relatively inexcitable motor cortex, with evidence of cortical dysfunction in the remaining 76.5% patients. Reduced resting motor threshold, and visuospatial performance, correlated with limb apraxia. Patients with a resting motor threshold <50% performed significantly worse on the visuospatial sub-task of the ACE-R than other CBS patients. Cortical function correlated with atrophy of the primary and pre-motor cortices, and the thalamus, while apraxia correlated with atrophy of the pre-motor and parietal cortices. Conclusions: Cortical dysfunction appears to underlie the core clinical features of CBS, and is associated with atrophy of the primary motor and pre-motor cortices, as well as the thalamus, while apraxia correlates with pre-motor and parietal atrophy
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